Luca de Alfaro worked at the foundations of formal verification, and wrote his Ph.D. dissertation on methods for the specification and model-checking of probabilistic systems. He contributed to the theory of component-based design of software and embedded systems, introducing the use of games as models for interacting components. He then delved in game theory, and in particular, in the theory of concurrent games, where players can choose moves simultaneously. He studied the properties of such games, and he devised solution methods for reachability, safety, and other common winning conditions. He extended the setting to stochastic games, and to games that can be played in real-time. From game theory, he became interested in reputation systems. With his group at UCSC, he built a content-based reputation system for Wikipedia, where authors would gain reputation by giving long-lasting contributions; he adapted the system to Google Map edits during a three-year industry stint at Google. Since then, he has worked on reputation systems, game theory, crowdsourcing, and more recently, data science and fairness in AI.